<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <link rel="stylesheet" href="./css/inputnumber.css" />
  <link rel="stylesheet" href="./css/index.css" />
  <title>购物车</title>
</head>

<body>
  <div class="app-container" id="app">
    <!-- 顶部banner -->
    <div class="banner-box"><img src="./img/fruit.jpg" alt="" /></div>
    <!-- 面包屑 -->
    <div class="breadcrumb">
      <span>🏠</span>
      /
      <span>购物车</span>
    </div>
    <!-- 购物车主体 -->
    <div class="main" v-show="fruitList.length>=1">
      <div class="table">
        <!-- 头部 -->
        <div class="thead">
          <div class="tr">
            <div class="th">选中</div>
            <div class="th th-pic">图片</div>
            <div class="th">单价</div>
            <div class="th num-th">个数</div>
            <div class="th">小计</div>
            <div class="th">操作</div>
          </div>
        </div>
        <!-- 身体 -->
        <div class="tbody">

          <div class="tr active" v-for="(item,index) in fruitList" :key="item.id" :class="{active:item.isChecked}">
            <!-- v-model="item.isChecked"双向绑定勾选框 -->
            <div class="td"><input type="checkbox" checked v-model="item.isChecked" /></div>
            <div class="td"><img :src="item.icon" alt="" /></div>
            <div class="td">{{item.price}}</div>
            <div class="td">
              <div class="my-input-number">
                <button :disabled="item.num<=1" class="decrease" @click="item.num--"> - </button>
                <span class="my-input__inner">{{item.num}}</span>
                <button class="increase" @click="item.num++"> + </button>
              </div>
            </div>
            <div class="td">{{item.num*item.price}}</div>
            <div class="td"><button @click="del(item.id)">删除</button></div>
          </div>


        </div>
      </div>
      <!-- 底部 -->
      <div class="bottom" v-show="fruitList.length>0">
        <!-- 全选 -->
        <label class="check-all">
          <!-- ================================================ -->
          <!-- 全选，反选v-model="isAll" -->
          <input type="checkbox" v-model="isAll" />
          <!-- ==================================================== -->
          全选
        </label>
        <div class="right-box">
          <!-- 所有商品总价 -->
          <span class="price-box">总价<span class="price">￥{{tonalPrice}}</span></span>
          <!-- 结算按钮 -->
          <button class="pay" @click="jie()">结算({{totalNum}})</button>
        </div>
      </div>
    </div>
    <!-- 空车 -->
    <div class="empty" v-show="fruitList.length<=0">🛒空空如也</div>
  </div>
  <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
  <script>
   
    const app = new Vue({
      el: '#app',
      data: {
        // 水果列表
        // 持久化储存
        fruitList: JSON.parse(localStorage.getItem('fruitList')) || [
          {
            id: 1,
            icon: './img/火龙果.png',
            isChecked: true,
            num: 2,
            price: 6,
          },
          {
            id: 2,
            icon: './img/荔枝.png',
            isChecked: false,
            num: 7,
            price: 20,
          },
          {
            id: 3,
            icon: './img/榴莲.png',
            isChecked: false,
            num: 3,
            price: 40,
          },
          {
            id: 4,
            icon: './img/鸭梨.png',
            isChecked: true,
            num: 10,
            price: 3,
          },
          {
            id: 5,
            icon: './img/樱桃.png',
            isChecked: false,
            num: 20,
            price: 34,
          },
        ],


      },


      // ======================================================================

      computed: {
        // ================================================================
        //  全选，反选 
        isAll: {
          get() {
            return this.fruitList.every(item => item.isChecked);
          },
          set(value) {
            this.fruitList.forEach(item => (item.isChecked = value));
          }
        },
        // ======================================================================
        // 优化写法
        checkedList() {
          return this.fruitList.filter(item => item.isChecked);
        },
        // 统计总价
        tonalPrice() {
          return this.checkedList.reduce((total, item) => total + item.price * item.num, 0);
        },
        // 统计选中总数
        totalNum() {
          return this.checkedList.reduce((total, item) => total + item.num, 0);
        },






        // 原本写法
        // // 总价
        // totalPrice(){
        //   return this.fruitList.filter((item)=>item.isChecked).reduce((sum,item)=>sum+item.price*item.num,0)
        // },

        // // 统计选中的数量
        // totalNum(){
        //   return this.fruitList.filter((item)=>item.isChecked).reduce((sum,item)=>sum+item.num,0)
        // }


      },
      // ========================================================================


      methods: {
        // 删除
        del(id) {
          this.fruitList = this.fruitList.filter(item => item.id !== id)
        },

        // // 水果个数加减
        // jia(id) {
        //   // 1. 根据 id 找到数组中的对应项 → find
        //   const fruit = this.fruitList.find(item => item.id === id)
        //   // 2. 操作 num 数量
        //   fruit.num++
        // },
        // // 水果个数加减
        // jian(id) {

        //   // 根据传入的 id 查找水果列表中对应的水果项
        //   const fruit = this.fruitList.find(item => item.id === id)

        //   if (fruit.num > 0) {
        //     fruit.num--
        //   } else {
        //     alert('不能再减了')
        //   }
        // },

        // 结算
        jie() {
          alert('结算成功')
        },



      },

      // 持久化存储 使用侦听器
      watch: {
        fruitList: {
          handler(newValue, oldValue) {
            localStorage.setItem('fruitList', JSON.stringify(newValue))
          },
          // 深度侦听
          deep: true
        }
      }


    })
  </script>
</body>

</html>